2calculate the missing numbers a) \( 20000: x=1000: 1 \)

To solve the proportion \( \frac{20000}{x} = \frac{1000}{1} \), you can cross-multiply. This gives you \( 20000 \cdot 1 = 1000 \cdot x \), leading to the equation \( x = \frac{20000}{1000} \). By simplifying that, you’ll find that \( x = 20 \). So, the missing number \( x \) is 20! Mathematics certainly has its little mysteries, but it can be quite rewarding once you find the answers.